The term "polyphenylene ether resin" includes a family of polymers well known to those skilled in the art, and they are made by a variety of catalytic and non-catalytic processes from the corresponding phenols or reactive derivatives thereof. By way of illustration, certain of the polyphenylene ethers are disclosed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875, and in Stamatoff, U.S. Pat. Nos. 3,257,357 and 3,257,358. In the Hay patents the polyphenylene ethers are prepared by an oxidative coupling reaction comprising passing an oxygen-containing gas through a reaction solution of a phenol and a metal-amine complex catalyst. Other disclosures relating to processes using metal-amine catalyst are found in Bussink et al, U.S. Pat. No. 3,337,499; Blanchard et al, U.S. Pat. No. 3,219,626; Laakso et al, U.S. Pat. No.. 3,342,892; Borman, U.S. Pat. No. 3,344,166; Hori et al, U.S. Pat. No. 3,384,619; Faurote et al, U.S. Pat. No. 3,440,217; and disclosures relating to metal based catalysts which do not include amines, are known from patents such as Wieden et al, U.S. Pat. No. 3,442,885 (copper-amidines); Nakashio et al, U.S. Pat. No. 3,573,257 (metal-alcoholate or -phenolate); Kobayashi et al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In the Stamatoff patents, the polyhenylene ethers are produced by reacting the corresponding phenolate ion with an initiator, such as peroxy acid salt, and acid peroxide, a hypohalite, and the like, in the presence of a complexing agent. Disclosures relating to non-catalytic processes, such as oxidation with lead dioxide, silver oxide, etc. are described in Price et al, U.S. Pat. No. 3,382,212. All of the above-mentioned disclosures are incorporated herein by reference.
The term "alkenyl aromatic resin" includes polymers and copolymers of styrene, alpha methyl styrene, chlorostyrene, ethylvinylbenzene, divinylbenzene, vinylnaphthalene and the like.
The term "EPDM" includes rubbery interpolymers of a mixture of monoolefins and a polyene. Preferred type are those rubbery interpolymers of ethylene, an alpha olefin and a polyene.
In the prior art rubber-modified styrene resins have been admixed with polyphenylene ether resins to form compositions that have modified properties. The Cizck patent, U.S. Pat. No. 3,383,435 discloses rubber-modified styrene resin-polyphenylene ether resin compositions wherein the rubber component is of the unsaturated type such as polymers of butadiene, or copolymers of butadiene and styrene. The physical properties of these compositions are such that it appears that many of the properties of the styrene resins have been upgraded, while the moldability of the polyphenylene ethers is improved.
Ger. Offen. Pat. No, 2,047,613 discloses that from 0.5-15% by weight of an EPDM modified styrene resin may be used to upgrade the impact strength of polyphenylene ether resin. There is no suggestion to use higher amounts or that higher amounts will improve the oxidative stability and color stability of a polyphenylene ether composition. Also no additional resinous materials are mentioned as components of the diclosed composition.
It has now been found that a composition of a polyphenylene ether resin; an alkenyl aromatic resin that is modified with a rubbery interpolymer of a mixture of monoolefins and a polyene; and an emulsion graft copolymer of an alkenyl aromatic resin and a rubbery interpolymer of a mixture of monoolefins and a polyene or a graft polymerization product of an acrylic monomer alone or in admixture with a styrene monomer and a rubbery diene homopolymer or copolymer of styrene and a diene is a very useful thermoplastic molding material which has good thermal oxidative stability and good impact strength.
It is, therefore, a primary object of this invention to provide improved compositions that are based on polyphenylene ether resins and modified alkenyl aromatic resins.
Another object of this invention is to provide molding compositions and molded articles that are based on a polyphenylene ether resin and a modified alkenyl aromatic resin which have improved thermal oxidative stability.
Still another object of this invention is to provide molding composition and molded articles that are based on a polyphenylene ether resin and a modified alkenyl aromatic resin which have, in addition, an emulsion grafted alkenyl aromatic resin and a rubbery interpolymer; or an emulsion grafted acrylic or acrylic and styrene polymer on a rubbery diene homopolymer or styrene-butadiene rubber backbone.
It is also an object of this invention to provide the above-described, improved molding compositions in reinforced and/or flame retardant embodiments.